Timing and abundance of sporangia production and zoospore release influences the recovery of different Phytophthora species by baiting

Sarker, Suchana R.; McComb, J.; Burgess, Treena I.; Hardy, G.E.St.J.

doi:10.1016/j.funbio.2021.01.009

Cited by 11 publications

(14 citation statements)

References 37 publications

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“…Phytophthora is commonly isolated using this method, and antimicrobials may be included in the media to suppress the growth of Pythium [10]. A sample may include several Phytophthora species, but only the dominant species are usually isolated [11]. Sarker et al [11] demonstrated competitive exclusion, whereby the species that rapidly produce sporangia were most frequently isolated.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Primers for the Detection of Phytophthora (and Other Oomycetes) from Environmental Samples

Burgess

White

Sapsford

2022

JoF

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Many oomycetes are important plant pathogens that cause devastating diseases in agricultural fields, orchards, urban areas, and natural ecosystems. Limitations and difficulties associated with isolating these pathogens have led to a strong uptake of DNA metabarcoding and mass parallel sequencing. At least 21 primer combinations have been designed to amplify oomycetes, or more specifically, Phytophthora species, from environmental samples. We used the Illumina sequencing platform to compare 13 primer combinations on mock communities and environmental samples. The primer combinations tested varied significantly in their ability to amplify Phytophthora species in a mock community and from environmental samples; this was due to either low sensitivity (unable to detect species present in low concentrations) or a lack of specificity (an inability to amplify some species even if they were present in high concentrations). Primers designed for oomycetes underestimated the Phytophthora community compared to Phytophthora-specific primers. We recommend using technical replicates, primer combinations, internal controls, and a phylogenetic approach for assigning a species identity to OTUs or ASVs. Particular care must be taken if sampling substrates where hybrid species could be expected. Overall, the choice of primers should depend upon the hypothesis being tested.

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Section: Introductionmentioning

confidence: 99%

Comparison of Primers for the Detection of Phytophthora (and Other Oomycetes) from Environmental Samples

Burgess

White

Sapsford

2022

JoF

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“…× cambivora . Our preliminary results must be confirmed by supplementary studies, which should take into account the timing of host competence assessments as sporangium production varies among Phytophthora species (Sarker et al, 2021). Such host differences for competence between both Phytophthora species, as well as in differences in pathogen functional traits, are likely to contribute to different epidemiological dynamics observed in chestnut ecosystems.…”

Section: Discussionmentioning

confidence: 62%

“…cinnamomi inoculum than P. × cambivora. Our preliminary results must be confirmed by supplementary studies, which should take into account the timing of host competence assessments as sporangium production varies among Phytophthora species (Sarker et al, 2021).…”

Section: Quantification Of P Cinnamomi Dna In Inoculated Seedlingsmentioning

confidence: 68%

Resistance, tolerance and competence for a root pathogen in six woody species

et al. 2022

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The outcome of host–pathogen interactions depends on host defence and pathogen infection strategies. On the host side, two strategies, resistance and tolerance, have long been identified. They differ in their underlying mechanisms and their effects on pathogens. However, the dynamics of disease transmission also rely on host competence. This trait, defined as the ability of the host to allow pathogen transmission, is rarely studied for pathogen‐supporting plants. We assessed the competence for Phytophthora cinnamomi of seedlings of five Quercus and one Castanea species and studied how this trait is correlated with resistance and tolerance. P. cinnamomi is responsible for the chestnut ink disease, alongside with Phytophthora × cambivora, which has a much less generalist behaviour. Each seedling was inoculated in minirhizotrons by root–mycelium contact and phenotyped for its resistance, tolerance and competence. The amount of necrosis (lesion length), the effect of infection on plant performance (root growth) and the sporangia number were measured. Moreover, we developed a droplet digital (dd) PCR assay to quantify the pathogen within host tissues near the inoculation point. This measure was used as a proxy of pathogen load. We were thus able to relate individual host competence to the pathogen content measured in the same root fragment. No significant correlation between the phenotyped traits was found at the individual level. However, at the species level, the least competent species (Q. robur, Q. petraea) proved to be the most resistant. These results may have important implications for management of chestnut and oak ecosystems threatened by ink disease.

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“…The difference in number of species detected through direct isolation (by soil/root baiting) versus metabarcoding has long been debated (Sarker et al 2023a). It is thought that in soil/root baiting, the isolation outcomes depend on Phytophthora propagules in the analysed samples since the method relies on motile zoospores released from the sporangia being attracted to a live bait (Sarker et al 2021). Baiting conditions favours fast-sporulating species, able to infect a range of bait species, achieve infection with a low number of zoospores, and fast-growing on selective agar (Sarker et al 2023a).…”

Section: Comparison Of Metabarcoding Molecular Detection Methods and ...mentioning

confidence: 99%

Oomycete compositon in Proteaceae orchards and natural stands on three continents

Migliorini

Vivas

Wingfield

et al. 2023

Preprint

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The Proteaceae is an important southern hemisphere family with many species known to be susceptible to Phytopthora cinnamomi, both in the natural environment and in cut-flower orchards. Very little in known about the prelevence of P. cinnamomi and other oomycetes across these landscapes. To address this lack of knowledge we a used double ITS1 and RSP10 gene metabarcoding approach and traditional isolation protocols to investigate oomycetes in orchards and natural stands of Proteaceae across four countries on different continents. Results revealed a consistent oomycetes richness within native and planted Proteaceae. Species richness and community composition were significantly influenced by the country of collection, while they did not show any variation between orchards and natural vegetation. RSP10 barcoding detected, the largest number of species and, provided a greater statistical confidence than ITS1 when considering oomycete species composition. Metabarcoding also showed that orchards had a higher abundance of P cinnamomi compared to native stands, but this outcome was not confirmed using isolation protocols.. These results and those of other recent studies show that metabarcoding provides an effective tool to describe the ecological dynamics of soil oomycetes in different ecosystems.

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Timing and abundance of sporangia production and zoospore release influences the recovery of different Phytophthora species by baiting

Cited by 11 publications

References 37 publications

Comparison of Primers for the Detection of Phytophthora (and Other Oomycetes) from Environmental Samples

Comparison of Primers for the Detection of Phytophthora (and Other Oomycetes) from Environmental Samples

Resistance, tolerance and competence for a root pathogen in six woody species

Oomycete compositon in Proteaceae orchards and natural stands on three continents

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